Nanofiber Films Research Articles

Reconfigurable intelligent surface and switchable electromagnetic interference shield based on dynamically adjustable composite film of cellulose nanofibers and VO2 nanoparticles

The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications.

Risperidone/cyclodextrin inclusion complex electrospun nanofibers for fast-disintegrating antipsychotic drug delivery

In this paper, the inclusion complexes (ICs) of hydroxypropyl-beta-cyclodextrin (HPβCD) and risperidone were electrospun into nanofibrous film for potential fast-disintegrating drug delivery system. Risperidone is used to treat bipolar disorder, schizophrenia, and mood swings from autism. However, it is practically insoluble in aqueous medium. On the other hand, the encapsulation of risperidone into HPβCD cavity by inclusion complexation can enhance water solubility of this drug molecule. Here, the IC systems were prepared with 4/1 and 2/1 M ratio (HPβCD/risperidone). The highly concentrated HPβCD aqueous solutions (200 %, w/v) were used for the fiber formation. Finally, the system having 4/1 M ratio resulted in a clear and homogeneous solution showing that the HPβCD and risperidone completely formed IC. However, HPβCD/risperidone-IC having 2/1 M ratio was turbid and contained some small clumps of un-complexed risperidone. Even so, free-standing and thin nanofibrous films were obtained for both systems with an average fiber diameter of ∼315 nm and ∼280 nm for 2/1 and 4/1 systems, respectively. Both HPβCD/risperidone-IC nanofibers were produced with approximately 100 % preservation of risperidone within the nanofiber matrix without the loss of risperidone during electrospinning process, that is, HPβCD/risperidone-IC nanofibers retained the initial M ratio of 2/1 and 4/1 as in electrospinning solution. Both HPβCD/risperidone-IC nanofibrous films showed fast-disintegration and fast-release characteristics in artificial saliva and aqueous medium verifying their potential as a fast-disintegrating oral drug delivery system for risperidone.

Novel cellulose-based films with highly efficient photothermal performance for sustainable solar evaporation and solar-thermal power generation

Solar-driven interfacial evaporation has received substantial attention in a variety of applications, including water purification, seawater desalination, and energy production. However, creating a straightforward, adaptable, and scalable method for correctly integrating hybrid solar-thermal systems continues to be a challenging task. Herein, we propose an economical, scalable, and environmentally friendly approach for achieving synergistic coupling of interfacial solar energy conversion for evaporation and low-grade thermal energy conversion to electricity by incorporating zinc oxide (ZnO) nanoparticle-modified MXene (ZNM- MXene) into cellulose nanofiber (CNF) films. The vacuum filtering approach produces CNF@ZNM-MXene composite films with enhanced photothermal conversion efficiency, capillary hydrophilicity, and thermal localization. Because of its rapid water transport capability, excellent sunlight absorption, and efficient solar-thermal conversion under 1 kW m−2 irradiance, the CNF@ZNM-MXene solar evaporator's evaporation rate reaches 1.27 kg m−2 h−1, and the solar-vapor conversion efficiency is as high as 82.15%, outperforming most previously reported solar evaporators. Moreover, when compared to a standalone thermoelectric (TE) module, the output power of the solar thermal conversion system coupled with a CNF@ZNM-MXene composite films and a TE module is boosted by 15.32 times. This work offers a practical and effective method for simultaneously capturing solar energy and desalinating saltwater.

Nanofiber Hydrogel Drug Delivery System for Prevention of Postsurgical Intestinal Adhesion.

Intestinal adhesion is one of the complications that occurs more frequently after abdominal surgery. Postsurgical intestinal adhesion (PIA) can lead to a series of health problems, including abdominal pain, intestinal obstruction, and female infertility. Currently, hydrogels and nanofibrous films as barriers are often used for preventing PIA formation; however, these kinds of materials have their intrinsic disadvantages. Herein, we developed a dual-structure drug delivery patch consisting of poly lactic-co-glycolic acid (PLGA) nanofibers and a chitosan hydrogel (NHP). PLGA nanofibers loaded with deferoxamine mesylate (DFO) were incorporated into the hydrogel; meanwhile, the hydrogel was loaded with anti-inflammatory drug dexamethasone (DXMS). The rapid degradation of the hydrogel facilitated the release of DXMS at the acute inflammatory stage of the early injury and provided effective anti-inflammatory effects for wound sites. Moreover, PLGA composite nanofibers could provide sustained and stable release of DFO for promoting the peritoneal repair by the angiogenesis effects of DFO. The in vivo results indicated that NHP can effectively prevent PIA formation by restraining inflammation and vascularization, promoting peritoneal repair. Therefore, we believe that our NHP has a great potential application in inhibition of PIA.

Layer-by-layer assembly of boron arsenide and copper nanoflake-based aramid nanofibers for thermoconductive electromagnetic interference shielding materials with superior mechanical flexibility and flame retardancy

Flexible and wearable electronics represent an emerging frontier, but realizing their potential requires addressing challenges like electromagnetic interference (EMI) shielding, electrical insulating thermal management, and mechanical flexibility. Layer-by-layer structure with alternating conductive and insulating layers offers a promising solution. In this work, we fabricated layer-by-layer structured papers combining boron arsenide (BA) as insulating layers and two-dimensional copper nanoflake (CuF) as conductive layers based on aramid nanofiber (ANF) film via alternating vacuum filtration. The resultant paper (BA4/CuF3) consists of 3 layers of CuF (50 wt%) based ANF (CuF@ANF) conductive layers sandwiched between 4 layers of BA (50 wt%) based ANF (BA/ANF) insulating layers providing exceptional EMI shielding effectiveness (SE) up to 52 dB in the X-band frequency, and in-plane thermal conductivity up to 32.8 W/mK. Meanwhile, the composite papers also demonstrate excellent mechanical flexibility, with the BA4/CuF3 papers exhibiting a tensile strength of 92.38 MPa and EMI SE above 50 dB. Moreover, the composites impart thermal stability up to 500 °C and reduce flammability. The concurrent enhancement of EMI shielding, thermal conductivity, and mechanical properties confirms the potential of layer-by-layer BA/CuF papers for next-generation flexible electronics demanding electromagnetic protection and thermal management.

Sandwich-Structured Mxene/Waste Polyurethane Foam Composites For Highly Efficient Electromagnetic Interference, Infrared Shielding and Joule Heating.

Electromagnetic interference (EMI) shielding and infrared (IR) stealth materials have attracted increasing attention owing to the rapid development of modern communication and military surveillance technologies. However, to realize excellent EMI shielding and IR stealth performance simultaneously remains a great challenge. Herein, a facile strategy is demonstrated to prepare high-efficiency EMI shielding and IR stealth materials of sandwich-structured MXene-based thin foam composites (M-W-M) via filtration and hot-pressing. In this composite, the conductive Ti3C2Tx MXene/cellulose nanofiber (MXene/CNF) film serves as the outer layer, which reflects electromagnetic waves and reduces the IR emissivity. Meanwhile, the middle layer is composed of a porous waste polyurethane foam (WPUF), which not only improves thermal insulation capacity but also extends electromagnetic wave propagation paths. Owing to the unique sandwich structure of "film-foam-film", the M-W-M composite exhibits a high EMI shielding effectiveness of 83.37dB, and in the meantime extremely low emissivity (22.17%) in the wavelength range of 7-14µm and thermal conductivity (0.19W m-1 K-1), giving rise to impressive IR stealth performance at various surrounding temperatures. Remarkably, the M-W-M composite also shows excellent Joule heating properties, capable of maintaining the IR stealth function during Joule heating.

Cellulose Nanofiber Films with Gold Nanoparticles Electrostatically Adsorbed for Facile Surface-Enhanced Raman Scattering Detection.

Cellulose nanofiber (CNF) holds great promise in applications such as surface-enhanced Raman scattering (SERS), catalysis, esthesia, and detection. This study aimed to build novel CNF-based SERS substrates through a facile synthetic method. Citrate-reduced gold nanoparticles (AuNPs) were adsorbed on the cationized CNF surface due to electrostatic interactions, and uniform AuNPs@(2,3-epoxypropyl trimethylammonium chloride)EPTMAC@CNF flexible SERS substrates were prepared by a simple vacuum-assisted filtration method. The probe molecule methylene blue was chosen to assess the performance of the CNF-based SERS substrate with a sensitivity up to 10-9 M, superior signal reproducibility (relative standard deviation (RSD) = 4.67%), and storage stability (more than 30 days). Tensile strength tests indicated that the CNF-based films had good mechanical properties. In addition, CNF-based substrates can easily capture and visually identify microplastics in water. These results demonstrate the potential application of the flexible, self-assembled AuNPs@EPTMAC@CNF flexible SERS substrate for prompt and sensitive detection of trace substances.

Aramid Nanofiber and Boron Nitride Nanosheet Composite Films for Mechanical and Dielectric Insulation Application

Aramid Nanofiber and Boron Nitride Nanosheet Composite Films for Mechanical and Dielectric Insulation Application

Triboelectric nanogenerator for Self-Powered musical instrument sensing based on the Ion-Electricfield-Migration Nylon/Na2SO4 nanofiber film

The advanced sensing technologies have a significantly important influence in promoting the design and research of intelligent musical instruments. Herein, we propose an ion-electricfield-migration enhanced triboelectric nanogenerator (IE-TENG) with the features of low-cost, lightweight and high-sensitive for the sensors of intelligent musical instruments. Compared to pure nylon nanofiber films, the voltage of IE-TENG with the nylon/Na2SO4 nanofiber films has been improved by 4.5 times, which is benefiting from the improved electrostatic induction of anions and cations migration. The fabricated IE-TENG sensor can achieve an excellent sensing performance with a sensitivity of 7.29 V N−1, a signal-to-noise ratio of 68.61 dB and a response-time of 10 ms, which are several times higher than the previous research works. Importantly, combined with the array structure design, multi-channel data acquisition and artificial intelligence digital analysis, an intelligent musical instrument system is constructed to gather and analyze the performer's playing information in real-time and quickly give the corresponding evaluation and improvement suggestions. Our finding not only give a good way for fabricating excellent performance TENG, but also promotes the application of TENG in intelligent musical instruments.

Electrospun superhydrophobic polyvinyl chloride /polydimethylsiloxane-nanodiamond nanocomposite with enhanced antifouling and mechanical properties for fresh produce packaging

Food package films serve the important functions of preserving food quality, extending shelf life, and protecting against external contaminants while also providing a barrier to moisture and oxygen. In consideration of the increasing frequency of foodborne outbreaks, there is a growing demand for food packaging films with additional functionality to prevent cross-contamination and the attachment of pathogens, thereby enhancing bacterial safety. Herein, we report a one-step fabrication approach relying on electrospinning of a blend of polyvinyl chloride (PVC) and polydimethylsiloxane (PDMS) together with nanodiamond (ND) on a rotating drum collector for the formation of bacterially antifouling food package films. In this approach, by adjusting the concentrations of PVC, PDMS, and ND and the drum angular velocity, the nanofiber diameter could be tuned in the range of 0.4 μm to 2.0 μm. Furthermore, these process parameters could also be used to modulate the water contact angle on the resultant films, with a minimum contact angle of 136.2 ± 5.6° and a maximum of 159.5 ± 3.8°. The lowest water contact angles were observed for films with bare PVC fibers while the highest contact angles were seen for films with nanocomposite fibers containing ND and PVC/PDMS. Compared with the films with bare PVC, nanocomposite films with ND-PVC/PDMS achieved up to 99.8 % and 99.6 % reduction in bacterial adhesion against S. typhimurium LT2 and Listeria innocua, respectively. The tensile strength of nanofibrous PVC film can be increased from 1.2 ± 0.4 MPa to 4.4 ± 0.3 MPa by the inclusion of PDMS (1:1 wt.%) and further increased to 8.9 ± 0.3 MPa with the additional inclusion of ND (PVC/PDMS/ND 1:1:0.1 wt.%). Considering the notable antifouling properties against bacteria and the improved mechanical characteristics, these nanocomposite films represent a noteworthy step in the development of sustainable and active food packaging solutions for a safer and healthier food supply chain.

Preparation, characterization, and the antimicrobial activity of PVA-PVP/ZnO nanofiber films via indigenous electrospinning setup

The study aimed to produce composite nanofibers (NFs) using the electrospinning method from Polyvinyl alcohol- Polyvinylpyrrolidone/Zinc oxide (PVA-PVP/ZnO) solutions. X-ray diffraction analysis confirmed that in the composite nanofibers, the relative intensity of the dominant crystal plane (101) associated with the wurtzite hexagonal structure of ZnO nanoparticles (NPs) decreased, and its broadness increased in the composite, indicating the presence of an amorphous part in the sample. The existence of functional groups from polymer systems was confirmed by Fourier-transform infrared spectroscopy (FTIR) spectral analysis. Field emission scanning electron microscope (FESEM) images revealed linear and branched uniform nanofiber structures with smooth surfaces of PVA-PVP/ZnO electrospun. The absorbance of PVA-PVP/ZnO NFs increased with the increase in ZnO NPs content, and an absorption band was observed in the ultra violet (UV) region at around 310 nm. The calculation of the optical energy gap using the absorption spectra fitting (ASF) approach roughly aligned with Tauc's model, ranging from 3.47 to 3.24 eV. The highest inhibition zone (14 and 15 mm) was observed at the ratios of 4 and 6 wt.% of ZnO NPs against gram-negative bacteria (Escherichia coli).

Synthesis of Nanosized γ-Cyclodextrin Metal-Organic Frameworks as Carriers of Limonene for Fresh-Cut Fruit Preservation Based on Polycaprolactone Nanofibers.

To address the issue of bacterial growth on fresh-cut fruits, this paper reports the synthesis of nanosized γ-cyclodextrin metal-organic frameworks (CD-MOFs) using an ultrasound-assisted method and their application as carriers of limonene for antibacterial active packaging. The effects of the processing parameters on the morphology and crystallinity of the CD-MOFs are investigated, and the results prove that the addition of methanol is the key to producing nanosized CD-MOFs. The limonene loading content of the nanosized CD-MOFs can reach approximately 170mg g-1. The sustained-release behaviors of limonene in the CD-MOFs are evaluated. Molecular docking simulations reveal the distribution and binding sites of limonene in the CD-MOFs. CD-MOFs are deposited on the surfaces of polycaprolactone (PCL) nanofibers via an immersion method, and limonene-loaded CD-MOF@PCL nanofibers are prepared. The morphology, crystallinity, thermal stability, mechanical properties, and antibacterial activity of the nanofibers are also studied. The nanofiber film effectively inhibits bacterial growth and prolongs the shelf life of fresh-cut apples. This study provides a novel strategy for developing antibacterial active packaging materials based on CD-MOFs and PCL nanofibers.

Free-standing ultra-thin carbon nanofiber films with controllable thickness for lithium ion batteries

Thin and porous anode materials enable short ion migration distances and high-rate performance. However, the current freestanding anode materials are too thick (typically around 100 μm) for high-rate lithium ion batteries (LIBs). Here, we have developed a facile and scalable process to synthesize ultra-thin (<400 nm) freestanding films. In comparison to other chemical and physical deposition methods that yield thin films (<500 nm), our freestanding films do not require the substrate material, achieving a 100 % loading of active material. Our ultra-thin carbon nanofiber films exhibit an exceptional specific capacity of 599 mAh/g even after 10,000 cycles at a current density of 10 A/g. Compared to thick carbon nanofiber films, the utilization of ultra-thin carbon nanofiber films as anode materials exhibits a remarkable enhancement of more than tenfold in cycling performance

Bio-Based Copolyester PEIFT: Enhanced Hydrophilicity, Rigidity, and Applications in Nanofibers.

The raw materials of Poly(ethylene terephthalate) (PET) are derived from petroleum-based resources, which are no sustainable. Therefore, previous researchers introduced biomass-derived 2,5-tetrahydrofurfuryl dimethanol (THFDM) into PET. However, its heat resistance has decreased compared to PET. In this paper, a novel bio-based copolyester, poly(ethylene glycol-co-2,5-tetrahydrofuran dimethanol-co-isosorbide terephthalate) (PEIFT), is prepared by introducing biomass-derived isosorbide (ISB) and THFDM into the PET chains through melting copolymerization process. With the introduction of ISB content, copolyesters' hydrophilicity and rigidity improve. Compared to PET, glass transition temperature (Tg) increases by over 5°C. In addition, the toughness and spinning performance of PEIFT have also been improved as a result of the addition of THFDM components. The hydrophobicity of PEIFTs electrospinning is greatly improved, with a contact angle exceeding 135°. Finally, due to the good hydrophobicity of PEIFTs nanofibers, they have potential application value in the manufacture of hydrophobic nanofiber and filter films. Given its biomass source and excellent performance, they make it easier to replace materials derived from petroleum.

Flexible piezoelectric sensor based on PAN/MXene/PDA@ZnO composite film for human health and motion detection with fast response and highly sensitive

Polyacrylonitrile (PAN) nanofiber-based flexible piezoelectric sensors are recognized for their applicability in wearable electronic devices, personal health monitoring, and motion detection. This research explores the impact of dual fillers, MXene and polydopamine-modified zinc oxide (PDA@ZnO), on the characteristics of PAN-based piezoelectric composite nanofiber films, including planar zigzag conformation content, dielectric, ferroelectric, piezoelectric, and mechanical properties. By integrating PDA@ZnO as a filler, PAN/MXene/PDA@ZnO-5 (PMPO) piezoelectric sensors were developed, showcasing enhanced piezoelectric sensing capabilities. These sensors achieved a sensitivity of 28.56 V/N across a broad linear range, with superior mechanical stability and durability across 3000 loading–unloading cycles, and exhibited swift response and recovery times of 49 ms and 40 ms, respectively. Furthermore, their unique fiber structure and flexibility, when interfaced with the human body, enable the detection of minute physiological movements and the conversion of varied motions into distinct voltage outputs. Thus, these sensors offer considerable promise for applications in human health monitoring and motion posture correction.

MXene/TPU Hybrid Fabrics Enable Smart Wound Management and Thermoresponsive Drug Delivery.

Thermoresponsive wound dressings with real-time monitoring and on-demand drug delivery have gained significant attention recently. However, such smart systems with stable temperature adjustment and drug release control are still lacking. Here, a novel smart fabric is designed for wound management with thermoresponsive drug delivery and simultaneously temperature monitoring. The triple layers of the fabrics are composed of the drug-loaded thermoresponsive nanofiber film, the MXene-optimized joule heating film, and the FPCB control chip. The precise and stable temperature stimulation can be easily achieved by applying a low voltage (0-4 V) to the heating film, achieving the temperature control ranging from 25 to 130 °C. And the temperature of the wound region can be monitored and adjusted in real time, demonstrating an accurate and low-voltage joule heating capability. Based on that, the drug-loaded film achieved precise thermoresponsive drug release and obtained significant antibacterial effects in vitro. The in vivo experiments also proved the hybrid fabric system with a notable antibacterial effect and accelerated wound healing process (about 30% faster than the conventional gauze group).

Doped nanofibers achieve tunable broadband in cholesteric phase liquid crystals

ABSTRACT In this study, polymer-stabilised cholesterol-based liquid crystal (PSLC) broadband reflective films were prepared by doping UV absorbers and chiral compounds in bilayer poly (methyl methacrylate) (PMMA) nanofiber films. Broadband reflection was achieved by diffusion of the UV absorber and chiral compounds in the bilayer nanofibers into the liquid crystal layer, which resulted in the formation of an inhomogeneous pitch distribution in the liquid crystal layer. To attain an optimal reflective effect, various factors such as polymer monomer concentration, concentration of chiral compounds in the spun film, diffusion temperature, diffusion time, and intensity of polymerised light were investigated. The effects of these factors on the reflective bandwidth were explored. The method significantly broadened the reflective bandwidth of the cholesteric phase liquid crystal layer, establishing the foundation for studying the combination of nanofiber films with cholesteric phase liquid crystals to form an adjustable pitch.

Deep Learning-Assisted Colorimetric/Electrical Dual-Sensing System for Ultrafast Detection of Hydrogen Sulfide.

This study presents a colorimetric/electrical dual-sensing system (CEDS) for low-power, high-precision, adaptable, and real-time detection of hydrogen sulfide (H2S) gas. The lead acetate/poly(vinyl alcohol) (Pb(Ac)2/PVA) nanofiber film was transferred onto a polyethylene terephthalate (PET) flexible substrate by electrospinning to obtain colorimetric/electrical sensors. The CEDS was constructed to simultaneously record both the visual and electrical response of the sensor, and the improved Manhattan segmentation algorithm and deep neural network (DNN) were used as its intelligent algorithmic aids to achieve quantitative exposure to H2S. By exploring the mechanism of color change and resistance response of the sensor, a dual-sensitivity mechanism explanation model was proposed to verify that the system, as a dual-mode parallel system, can adequately solve the sensor redundancy problem. The results show that the CEDS can achieve a wide detection range of H2S from 0.1-100 ppm and identify the H2S concentration in 4 s at the fastest. The sensor can be stabilized for 180 days with excellent selectivity and a low limit of detection (LOD) to 0.1 ppm of H2S. In addition, the feasibility of the CEDS for measuring H2S levels in underground waterways was validated. This work provides a new method for adaptable, wide range of applications and low-power, high-precision H2S gas detection.

Cellulose nanowhiskers‐reinforced polymer nanofibers for photoresponsive authentication

AbstractThe objective of the current study is to develop novel photochromic polyurethane (PUR) nanofibrous films supported with cellulose nanowhiskers (CNW) and immobilized with nanoparticles of alkaline‐earth doped aluminate (NAEA) using the highly efficient and low‐cost solution blowing spinning (SBS) technique. CNW revealed a crystal diameter of 4–8 nm, and a crystal length of 55–105 nm. The solution blown spun nanofibers exhibited diameters of 250–450 nm. In order to prepare a transparent film, CNW and NAEA must be dispersed efficiently in the PUR composite. When supported with CNW, the efficiency of PUR nanofibrous films was strengthened. Cellulose paper sheets were coated with the colorless NAEA/CNW@PUR films to emit a green light at 518 nm upon excitation at 365 nm as proved by photoluminescence spectra. The prepared nanofibrous films exhibited efficient optical photochromic characteristics for potential security encoding applications. The nanofibers‐coated papers showed high photochromic reversibility without fatigue. The current approach can be reported as an efficient technology for authentication of commercial products.

Self-powered wearable human-computer interaction system based on kapok cellulose nanofibers

As wearable devices in the fields of medical health, human–computer interaction, and motion detection continue to diversify in their materials and forms, they show vast application potential. Cellulose materials are emerging as prominent materials for fabricating flexible wearable electronic devices because of their favorable skin compatibility, cost-effectiveness, and abundance. However, there is little research on the use of kapok cellulose in wearable electronics. This study addresses this knowledge gap by exploring the high-yield production and waste recycling potential of kapok cellulose. To overcome the limitations of conventional cellulose films, such as poor flexibility, high haze, and limited light transmittance, a kapok cellulose nanofiber film (KCNF) with a transparency of > 90 % and a tensile strain of > 20 % is prepared. The use of the KCNF as a friction electric material in the triboelectric nanogenerator (TENG) improves its electrical output performance by 228 % and permits its comfortable long-term attachment to the skin for self-powered tactile sensing applications, including game control, text input, and smart medical devices. This study demonstrates that the exploration of KCNF materials expands the options available for developing wearable electronic devices with numerous potential applications.